This section is intended to provide a background or context to the invention that is recited in the claims. The description herein may include concepts that could be pursued, but are not necessarily ones that have been previously conceived, implemented or described. Therefore, unless otherwise indicated herein, what is described in this section is not prior art to the description and claims in this application and is not admitted to be prior art by inclusion in this section.
The following abbreviations that may be found in the specification and/or the drawing figures are defined as follows:
BS base station
BW bandwidth
CA carrier aggregation
CC component carrier
CoMP coordinated multi-point (transmission or reception)
CRS cell-specific reference symbols
CSI channel state information
CSI-RS channel state information reference symbols
DCI downlink control information
DFT discrete Fourier transform
DL downlink (from the network to a UE)
DM RS demodulation reference signal
eNB, eNodeB EUTRAN Node B (evolved Node B/base station)
EPC evolved packet core
EUTRAN evolved universal terrestrial access network
MAC medium access control (layer 2, L2)
MIMO multiple input multiple output
MM/MME mobility management/mobility management entity
OFDMA orthogonal frequency division multiple access
PDCCH physical downlink control channel
PDCP packet data convergence protocol
PDSCH physical downlink shared channel
PHY physical (layer 1, L1)
PL pathloss
PMI precoding matrix indicator
PRB physical resource block
PUSCH physical uplink shared channel
RLC radio link control
RRC radio resource control
RRH remote radio head
RS reference symbol
RSRP reference symbol received power
RSRP reference symbol received quality
Rx or RX reception or receiver
SC-FDMA single carrier-frequency division multiple access
SGW, SG-W serving gateway
SRS sounding reference symbols
TPC transmit power control
Tx or TX transmission or transmitter
UE user equipment (e.g. mobile terminal)
UL uplink (from a UE to the network
UPE user plane entity
One modern communication system is known as evolved UTRAN (E-UTRAN, also referred to as UTRAN-LTE or as E-UTRA). FIG. 1 reproduces FIG. 4-1 of 3GPP TS 36.300 and shows an overall architecture of the EUTRAN system. The E-UTRAN system includes eNBs, providing the E-UTRAN user plane (PDCP/RLC/MAC/PHY) and control plane (RRC) protocol terminations towards the UEs. The eNBs are interconnected with each other by means of an X2 interface. The eNBs are also connected by means of an S1 interface to an EPC, more specifically to a MME by means of a S1 MME interface and to a S-GW by means of a S1 interface (MME/S-GW). The S1 interface supports a many-to-many relationship between MMEs/S-GWs/UPEs and eNBs. In this system, the DL access technique is OFDMA, and the UL access technique is SC-FDMA. The EUTRAN system shown in FIG. 1 is one possible system in which the exemplary embodiments of the instant invention might be used.
Of particular interest herein are the further releases of 3GPP LTE (e.g., LTE Rel-10, LTE Rel-11) targeted towards future IMT-A systems, referred to herein for convenience simply as LTE-Advanced (LTE-A). LTE-A is specified in Rel-10 (see, e.g., 3GPP TS 36.300 v10.3.0 (2011-03)), further enhancements in Rel-11. Reference in this regard may also be made to 3GPP TR 36.913 V9.0.0 (2009-12) Technical Report 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Requirements for further advancements for Evolved Universal Terrestrial Radio Access (E-UTRA) (LTE-Advanced)(Release 9). Reference can also be made to 3GPP TR 36.912 V9.3.0 (2010-06) Technical Report 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Feasibility study for Further Advancements for E-UTRA (LTE-Advanced) (Release 9).
A goal of LTE-A is to provide significantly enhanced services by means of higher data rates and lower latency with reduced cost. LTE-A is directed toward extending and optimizing the 3GPP LTE Rel-8 radio access technologies to provide higher data rates at lower cost. LTE-A will be a more optimized radio system fulfilling the ITU-R requirements for IMT-Advanced while keeping the backward compatibility with LTE Rel-8.
Coordinated multi-point (CoMP) reception is considered for LTE-A as a tool to improve the coverage of high data rates. In this type of system, multiple geographically separated points and antenna(s) at these points receive signals from multiple user equipments. The signals then need to be combined in order to determine data from the user equipments. Typical techniques for combining these signals can be too complex.